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611.
Ann-Christine Albertsson Mikael Gröning Minna Hakkarainen 《Journal of Polymers and the Environment》2006,14(1):9-13
Emission of low molar mass compounds from different polymeric materials was determined and the results from the volatile analysis
were applied to predict the degree of degradation and long-term properties, to determine degradation rates and mechanisms,
to differentiate between biotic and abiotic degradation and for quality control work. Solid-phase microextraction and solid-phase
extraction together with GC-MS were applied to identify and quantify the low molar mass compounds. Volatiles were released
and monitored at early stages of degradation before any matrix changes were observed by e.g. SEC, DSC and tensile testing.
The analysis of volatiles can thus also be applied to detect small differences between polymeric materials and their susceptibility
to degradation. The formation of certain degradation products correlated with the changes taking place in the polymer matrix,
these indicator products could, thus, be analysed to rapidly predict the degree of degradation in the polymer matrix and further
to predict the long-term properties and remaining lifetime of the product. 相似文献
612.
John H. Rodgers R. S. Harvey 《Journal of the American Water Resources Association》1976,12(6):1109-1118
ABSTRACT: Productivity measurements of organisms attached to artificial substrates ranged from 6.5–7.6 mg C/m2/hr and were 17-65% greater in stirred bottles (simulated flow) than under static conditions. Carbon-14 was used to determine the effect of current on the primary productivity of these organisms in six artificial streams at the Flowing Streams Laboratory on the Savannah River Plant (U.S. Energy Research and Development Administration, Aiken, South Carolina, U.SA.). Seasonal changes in dominant organisms were monitored from June 1973 to March 1974. Estimates of productivity, accumulated biomass, and levels of chlorophyll a were compared for possible correlation. Production of chlorophyll a ranged from 50 to 381 mg/m2, and accumulated biomass ranged from 45 to 181 g/m2 on the artificial substrates (glass microscope slides) during the period of study. Productivity of attached organisms was generally an order of magnitude greater than productivity of phytoplankton or tychoplankton. The consistently higher productivity in simulated flowing systems than in static systems tends to cast some doubt on values obtained when lotic communities have been enclosed or isolated in chambers or bottles without inducing a current or stirring action. 相似文献
613.
采用SBR反应器驯化培养反硝化聚磷菌,考察了厌氧-缺氧-好氧和厌氧-缺氧运行模式下反硝化聚磷菌的增殖情况、反应器的脱氮除磷特性及胞内聚合物聚β-羟基丁酸(PHB)和糖原的合成消耗情况。实验结果表明:经过72 d(288个周期)的驯化培养,SBR反应器内反硝化聚磷菌的数量约占全部聚磷菌的84.5%;厌氧-缺氧培养方式下,反硝化聚磷菌的释磷速率为34.5 mg/(L·h),缺氧吸磷速率为23.0 mg/(L·h),缺氧阶段每降解1.0 mg/L的PO_4~(3-)-P需要消耗1.0 mg/L的NO_3~--N;每消耗6.3 mg/L的COD生成1 mg/g的PHB,每降解1 mol的PHB约生成0.73 mol的糖原。 相似文献
614.
CDPVA是一种具有共轭多烯序列的聚乙烯醇(PVA)衍生物。通过低温热处理法制备了CDPVA/ZnO复合光催化剂。表征结果显示,PVA经低温热处理后形成了具有一定共轭结构的CDPVA并包覆于纳米ZnO颗粒表面,提高了光催化剂的可见光响应能力,有效促进了光生空穴和电子的分离。当PVA与纳米ZnO的质量比为1∶100时,CDPVA/ZnO的可见光催化活性最高;在催化剂投加量为0.5 g/L、初始罗丹明B质量浓度为4 mg/L、可见光照射50 min的条件下,罗丹明B降解率为97.51%,明显优于纯纳米ZnO;CDPVA/ZnO循环使用9次后仍保持较高的罗丹明B降解率,表明CDPVA的包覆有效抑制了纳米ZnO的光腐蚀,提高了光催化剂的稳定性。 相似文献
615.
616.
The depth profile of mercuric ion after the reaction with polysulfide-rubber-coated activated carbon (PSR-AC) was investigated using micro-X-ray fluorescence (μ-XRF) imaging techniques and mathematical modeling. The μ-XRF results revealed that mercury was concentrated at 0-100 μm from the exterior of the particle after 3 months of treatment with PSR-AC in 10 ppm HgCl2 aqueous solution. The μ-X-ray absorption near edge spectroscopic (μ-XANES) analyses indicated HgS as a major mercury species, and suggested that the intra-particle mercury transport involved a chemical reaction with PSR polymer. An intra-particle mass transfer model was developed based on either a Langmuir sorption isotherm with liquid phase diffusion (Langmuir model) or a kinetic sorption with surface diffusion (kinetic sorption model). The Langmuir model predicted the general trend of mercury diffusion, although at a slower rate than observed from the μ-XRF map. A kinetic sorption model suggested faster mercury transport, which overestimated the movement of mercuric ions through an exchange reaction between the fast and slow reaction sites. Both μ-XRF and mathematical modeling results suggest mercury removal occurs not only at the outer surface of the PSR-AC particle but also at some interior regions due to a large PSR surface area within an AC particle. 相似文献
617.
不同类型清洗剂对含聚油泥清洗效果及界面性质的影响 总被引:4,自引:0,他引:4
为解决聚驱采出液中产生的大量含聚油泥造成石油资源浪费和环境污染问题,选用化学清洗法对含聚油泥进行处理。不同类型化学清洗剂对含聚油泥清洗效果的规律是:无机型和非离子型清洗剂对含聚油泥清洗效果最好,阴离子型清洗剂次之,阳离子型清洗剂最差。优化了无机清洗剂Na2SiO3和非离子型清洗剂EL100的脱油条件,脱油率分别达到91.12%和85.59%。不同类型清洗剂清洗含聚油泥的脱油率与油水界面性质具有明显的关联性,即脱油率越高,水相电导率越小,油滴Zeta电位绝对值越小,油滴中值粒径越大,油水界面张力越小。 相似文献
618.
Bustamante M Tajadura-Martín FJ Saiz-Salinas JI 《Environmental monitoring and assessment》2007,134(1-3):397-410
The Bilbao estuary (northern Spain) has suffered a serious environmental deterioration due to industrial and domestic discharges
during decades. A total of 21 sampling stations were selected in order to: (1) study the intertidal fauna distribution on
both hard and soft bottoms; (2) link this information with the prevalence of certain environmental variables at the sampling
sites; and (3) define distinct biological zones with all the information gathered. Up to 50 taxa were identified mainly in
the outer estuary with an abrupt decrease upstream. In general, fauna on hard substrates was more diverse, while soft bottom
communities exhibited a more consistent structure. Sporadic hypoxic events were recorded in the water column of all the sites
studied, which affects the distribution of species. Three major biotic zones are proposed in the estuary. This provides a
reliable biomonitoring tool for assessing the effectiveness of a sewerage and remediation scheme ongoing on the river and
evaluating the future use of each area in the urban development of the city of Bilbao and conurbation. 相似文献
619.
通过改变培养基中ρ(TP),并结合TOC(总有机碳)分析、考马斯亮蓝法、蒽酮硫酸法和茚三酮法研究不同ρ(TP)对水华中常见绿藻——四尾栅藻的生长规律及其IOMs(胞内有机物)和EOMs(胞外有机物)中TOC、蛋白质、碳水化合物和氨基酸代谢规律的影响. 结果表明,随着ρ(TP)的增加,四尾栅藻生长的指数期变长. ρ(TP)为0.01 mg/L时有利于四尾栅藻EOMs中碳水化合物的形成与积累,ρ(碳水化合物)在指数期达到最大,为89.25 mg/L;ρ(TP)为0.20 mg/L时则有利于四尾栅藻EOMs中氨基酸的形成,并且ρ(氨基酸)在稳定期达到最大,为13.72 mg/L. ρ(TP)为0.01 mg/L时有利于四尾栅藻IOMs中氨基酸的形成,ρ(氨基酸)在指数期达到最大值(21.85 mg/L). 利用EEM(三维荧光)对四尾栅藻的EOMs和IOMs进行表征发现,ρ(TP)的改变会对四尾栅藻IOMs和EOMs中不同物质的峰强产生影响;同时,随着藻细胞的生长,ρ(TP)也会影响四尾栅藻EOMs中的物质组成. 相似文献
620.